Water level go below skimmer weir level?

Question

Above ground pool, skimmer + 2 drains connected to pump. What happens if I let water level go below skimmer weir level? Will pump lose prime?

Thanks.

Answer 1

Quite probably, depending on how it's plumbed. Water is lazy and will take the easiest route. This sounds almost like a typical Kayak Pool's suction layout, that has a bottom wall suction as well as the skimmer all tied into one line going to the pump and no isolation valves. That being the case, eventually the skimmer will run dry and introduce air, causing the pump to lose it's prime temporarily. The skimmer line then will refill to the current water level, equalize , the pump gets it's prime back and the whole process starts again. That gets pretty hard on the pump's shaft seal and will shorten it's life.

Then again, you say you have two suction lines going to near or at the bottom. Both together, if they have few elbows, may keep that pump primed, particularly if there are more elbows or longer run on the actual skimmer line and it can also depend on any T's and how they are plumbed as well. Water is lazy. :)

If you installed either a gate or ball valve between the skimmer and where it T's  to tie into your bottom suctions, your pool will still run even if the level gets below the skimmer. I'm willing to bet that they used 1 1/4 inch pipe and even with only one suction source, your pump won't starve since it'll be an above ground pool pump that doesn't have the flow rate of an inground pump. Heck, it's probably plumbed 1 1/4 right to the pump for that matter with no bushing bringing it up to 1 1/2 inch at the pump wet end.

Answer 2

That along with the fact that if you run any type of a water pump without water for to long you will burn the pump out.